The present invention relates to a diagnosis system for a motor vehicle.
Recently, a motor vehicle has been equipped with an electronic control system for controlling various components of an engine, such as fuel injectors, thereby improving driveability, exhaust gas emission, fuel consumption and engine power. The electronic control system controls the components based on information represented by output signals from various sensors for detecting engine operating conditions. Accordingly, if malfunctions of components and sensors occur, the engine does not properly operate.
However, because of the complexity of the electronic control system, it is difficult to immediately find out trouble. Accordingly, a trouble diagnosis device for easily checking the electronic control system should be provided in an auto shop. The electronic control system has a memory and a communication system to be connected to the trouble diagnosis device.
Since the address of the memory and the communication system differ with different types of motor vehicles, an identification code of a type of motor vehicle is stored in the memory. The diagnosis device discriminates the vehicle type based on the identification code.
Japanese patent application Laid-Open 58-12848 discloses a diagnosis system in which an exclusive checking device is provided for diagnosing operations of various sensors and actuators. However, the checking device is provided for diagnosing only designated specific types of motor vehicle.
Although, a diagnosis system can store a plurality of control programs for diagnosing various types of motor vehicles in a memory, control programs for all types of motor vehicle can not be stored in the memory.
On the other hand, there is a case where diagnosis can be performed with a program for another type of vehicle. However, since the identification code is different from the other one, the program cannot be used.